This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 146880 |
| 3 | 64757760 |
| 4 | 4844836800 |
| 5 | 137695887360 |
| 6 | 2121555283200 |
| 7 | 21421110804480 |
| 8 | 158757684004800 |
| 9 | 928986331545600 |
| 10 | 4512164186816640 |
| 11 | 18847854517248000 |
| 12 | 69519016873985280 |
| 13 | 230952108679004160 |